Menu

Discussion Forum

New Discussion
Filter

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

mutual inductance in 3D

Posted Jan 27, 2014, 7:47 a.m. EST Low-Frequency Electromagnetics Version 4.4 7 Replies

David Segal
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi

There have been some posts on this issue but no clear resolution to the problem.
Say we have 2 randomly shaped coils at random 3D orientation. Find mutual inductance with 1% accuracy.
One method would be to inject a current in one coil and find voltage in the other.
If you try the Magnetic fields model as in the Comsol 2D example you find it is not easy defining
the terminals on the 3D boundaries (especially if you include the infinite boundary feature).
The terminals can only be defined on an external boundary.
Question is also how heavy the mesh must be to achieve desired accuracy.
thanks for any advice
David
7 Replies Last Post Jan 29, 2014, 10:31 a.m. EST
kishore naik
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 27, 2014, 8:50 a.m. EST

Dear david,
You can use multi turn coil domain feature in 3D also . And you can find mutual inductance by mf.VCoil_2/mf.ICoil_1/mf.iomega
--
kishore Naik Mude
Dear david, You can use multi turn coil domain feature in 3D also . And you can find mutual inductance by mf.VCoil_2/mf.ICoil_1/mf.iomega -- kishore Naik Mude
David Segal
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 27, 2014, 9:59 a.m. EST
Hi

thanks. My problem is with a pair of planar spiral inductors . multiturn coil will not work here
Hi thanks. My problem is with a pair of planar spiral inductors . multiturn coil will not work here
Dennis Brown
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 27, 2014, 3:15 p.m. EST

Question is also how heavy the mesh must be to achieve desired accuracy.
thanks for any advice
David


I would start with a coarser mesh and then tighten it up and see how the results change. This is called a mesh study. Just a way to see how fine you have to make a mesh before you see diminishing returns on the results.
[QUOTE] Question is also how heavy the mesh must be to achieve desired accuracy. thanks for any advice David [/QUOTE] I would start with a coarser mesh and then tighten it up and see how the results change. This is called a mesh study. Just a way to see how fine you have to make a mesh before you see diminishing returns on the results.
David Segal
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 27, 2014, 4:43 p.m. EST
Hi

thanks the meshing is actually a minor issue. The main question is how to set up the model
Hi thanks the meshing is actually a minor issue. The main question is how to set up the model
Dennis Brown
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 28, 2014, 8:34 a.m. EST
It would be better if you posted the actual model or something close to it (if it is proprietary in nature) but in generic terms, you will most likely have to place the coils inside an airbox. The airbox sides will be "ground" so you have see to it that you can place lumped ports at coil input. Make the airbox big enough but not too big as a first cut. There is a model in the comsol model gallery of a 3D inductor. That one is in enclosed in an airbox and could serve as a good kickoff/reference point. Take a look at the online models, see what does/doesn't make sense, and if you have other questions please post them.
It would be better if you posted the actual model or something close to it (if it is proprietary in nature) but in generic terms, you will most likely have to place the coils inside an airbox. The airbox sides will be "ground" so you have see to it that you can place lumped ports at coil input. Make the airbox big enough but not too big as a first cut. There is a model in the comsol model gallery of a 3D inductor. That one is in enclosed in an airbox and could serve as a good kickoff/reference point. Take a look at the online models, see what does/doesn't make sense, and if you have other questions please post them.
kishore naik
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 29, 2014, 10:31 a.m. EST
I am having same issue with spiral coils, I applied a external current density on the coils, i can find inductance by energy method , but mutual inductance i am not able to. Please suggest

--
kishore Naik Mude
I am having same issue with spiral coils, I applied a external current density on the coils, i can find inductance by energy method , but mutual inductance i am not able to. Please suggest -- kishore Naik Mude
kishore naik
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jan 29, 2014, 10:31 a.m. EST
I am having same issue with spiral coils, I applied a external current density on the coils, i can find inductance by energy method , but mutual inductance i am not able to. Please suggest

--
kishore Naik Mude
I am having same issue with spiral coils, I applied a external current density on the coils, i can find inductance by energy method , but mutual inductance i am not able to. Please suggest -- kishore Naik Mude

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content